Rubberless elastic fabric



Sept. 15, 1931. s W N 1,823,053

RUBBERLESS ELA STIC FABRIC Filed Oct. 31. 1930 0K J INVENTOR BY 1% I A ATTORNEYj Patented Sept. 15, 1931 UNITED STATES PATENT OFFICE OSCAR S. LA'WTON, OF NEW BEDFORD, MASSACHUSETTS, ASSIGNOR TO ELASTIC WEAVE PRODUCTS, LNG, OF NEW YORK, N. Y., A CORPORATION OF DELAWARE RUBBEBLESS ELASTIC mam Application filed October 31, 1930. Serial No. 492,414.

The present invention relates to an im proved elastic material and method of making the same. More especially the invention relates to the manufacture of elastic thread or fabric which is composed of a fibrous material of a sort that is ordinarily considered to be relatively inelastic, and the invention proposes to provide an elastic thread or fabric composed of cotton, silk, wool, or linen.

Elastic fabrics made either wholly or in part of india rubber have a wide use in the manufacture of various articles, chiefly articles of apparel, such for example as waistbands, garters, armbands, inserts in mens underwear, in certain kinds of shoes or house slippers, and the like. The employment of rubber in elastic materials for such uses has certain disadvantages, among which are a limitation of the useful life of the material because of the relatively rapid deterioration of the rubber, the liability of permanent injury to the rubber even when the articles are relatively new, by subjection to high temperatures, either inadvertently or during the cleansing or washing of the garments into which the rubber elastic material has been incorporated. Moreover, there are certain disadvantages in the manufacture of elastic fabrics in which rubber is employed, caused by the fact that a highly elastic material must be subjected to special treatment during the weaving, and other manufacturing operations, while such precautions need not be taken in weaving ordinary fabrics.

It is the primary object of'the present invention to provide a rubberless material, and particularly a rubberless fabric which possesses suflicient elastic properties to enable its successful employment for many purposes in place of elastic material containing india rubber.

It is another object of the invention to provide a rubberless elastic material, the elastic properties of which tend to increase, or at least maintain, substantially their original effectiveness with use instead of deteriorating with use, as in the case of india rubber.

Another object of the invention is to provide a rubberless elastic material which possesses the property of potential elasticity, or

in other words, a material in which the elastic properties thereof remain inert or latent until it is desired to develop them.

The present invention is directed especially to the improvement of the rubberless elastic material and the method of making the same which is disclosed in the co-pending application of Harold P, Dworsky and Oscar S. Lawton, Serial No. 296,481 filed July 31, 1928. The rubberless elastic material made in accordance with the disclosure of that application possesses a high degree of elasticity and retractile force. Nevertheless in the uses for which this material is intended, namely, for waistbands, garters, and the like, it is desirable to construct the material in such a way that it will possess the highest possible amount of retractile force and elasticit and by the present invention I have provi ed an elastic material made from relatively inelastic fibrous material which possesses an even higher degree of retractile force and elasticity than that disclosed in the above-mentioned application.

In accordance with the present invention I increase the original count of the yarn (i. e. the length per unit of weight) by moistening (that is, wetting) and stretching, thereby reducing the size or gauge of the yarn and enabling it to receive a greater amount of twist, or turns per unit of length, than the yarn was capable of receiving in its original size. As the twist increases the tension is increased sufiiciently to keep the yarn straight or unkinky. The moistened and stretched yarn is twisted preferably to the point where either the yarn will break if twisted farther or kink if the tension is reduced. The yarn is permitted to dry in such stretched and highly twisted condition.

The yarn in this form is not elastic but is potentially elastic like the yarn of the prior application. In order to render the yarn elastic, the tension is removed and the yarn is moistened (that is, wetted) and dried in its free state, that is, without being subjected to tension or stretching. This final moistening of the yarn causes the yarn to return to a lower count or lar er size, retaining, however, substantially al l of the extremely large amount of twist which has been imparted to it.

While the moistening, stretching and twisting of the yarn may be done in the order just described, it is most convenient to carry on all three of these operations simultaneously. In other words, the yarn is moistened while it is being twisted. Also the yarn may be stretched and twisted while dry, then moistened, and then subjected to further twisting. The important consideration is that the yarn be twisted after having been moistened and stretched so as to impart a greater number of turns to the yarn than the yarn would take either in its original count, or when stretched and twisted while dry.

The moistening or wetting may be accomplished by passing the yarn through a liquid bat-h, or by the use of steam or water vapor at a moderately warm temperature. A high temperature is not necessary and saturated steam in .the neighborhood of 212 F. is quite satisfactory. Vapor at a lower temperature than this is also satisfactory. In practice also the moistened, stretched and highly twisted yarn is-wound upon spools under a winding tension which is sufficient to maintain the yarn in the highly twisted and unkinky or straight condition. The yarn is thoroughly driedafter winding upon these spools and after drying it may be stored for subsequent use.

It will be understood that the yarn after this drying operation is in its increased count, or reduced size, but is in highly twisted potentially elastic condition and will remain in this condition after the removal of the winding tension. Hence the dry yarn can be removed from the spools and placed in the warping frame, or otherwise used, as readily and easily as ordinary yarn.

This potentially elastic yarn, after weaving, is rendered highly elastic by the final moistening operation which may be carried on in any suitable and convenient manner sufficient to insure thorough penetration of the mass of yarn fibers. This final moistening operation causes the .yarn to return to a lower count, or increasedsize, but retaining the large number of turns which have been imparted to it while it was in its increased count, and which causes it to assume a kinky or spring-like shape.

The invention will be better understood from a consideration of the accompanying drawings in which Figs. 1 to 5 inclusive are very greatly magnified and more or less diagrammatic views of a small section of yarn shown under various conditions of twist and tension.

Fig. 6 is a somewhat enlarged plan view of a short length of a fabric woven with warp threads made in aecordance with my invention, these threads being in potentially elastic condition, that is, not having been subjected to the final moistening and drying op erations.

Fig. 7 is a sectional view of the fabric Sl'l(()1WI1 in Fig. 6 taken on line 7-7 of Fig. (5, an

Fig. 8 is a plan view of the fabric shown in Fig. 6 after having been subjected to the final moistening and drying operations, showing the helical or spring-like shape which the warp threads assume by the final moistening in the free state.

Referring now to the accompanying drawings, Fig. 1 illustrates a short length of normal yarn, that is, yarn of ordinary twist as it comes from the mill before being treated in accordance with the invention. The selection of this yarn as to size and material is dictated .by the texture and character of the fabric which it is desired to produce, having in mind the use to which the fabric is to be put. F or making elastic fabric for use in waistbands, for example, a24s-2-ply' yarn is suitable: This means that the yarn is made of two plies and each of the two plies has a yarn count of twenty-four, that is, there are twenty-four times as many yards in a pound as there are in a pound of yarn of number one count. This constant is sometimes termed the multiplier. The usual amount of twist in normal yarn is from about five to about seven times the square root of the yarn count. The direction of twist of the ply in the yarn ma of the fibers in the single, that is, regulaf twist, but preferably I employ a twist on twist yarn, that is, a yarn in which the direction of twist of the plies in the yarn is the same as the direction of twist of the fibers in the single. By employing a twist on twist am, the addltional twist or turns which I impart to the yarn serve to increase rather than decrease the twist of the fibers in the single. In the following description, however, it will be understood that a regular twist yarn is referred to. It will be further understood that the appended claims include the employment of a twist on twist yarn. in which case the'same equivalent twist of the plies in the yarn is denoted by the use of a lower multiplier.

The material of the yarn is preferably cotton, althou h other materials as mentioned above may be used.

The sloping dotted line shown at the left of Figs. 1 to 5 indicates in a general way the amount of twist in the normal yarn shown in Fig. 1 and forms a basis for a rough comparison of the change in twist of the yarn illustrated'in Figs. 2 to 5 inclusive.

Fig. 2 of the accompanying drawings illustrates the yarn shown in Fig. 1 after having, imparted therein the maximum twist which the yarn will take in its original count. This is generally accepted as being in the neighborhood of twelve times the square root of be opposite to the direction of twist the yarn count and is known as a crepe twist. If theyarn is twisted to a greater extent than this it is apt to be destroyed by the impartation of any further twist. If we assume by way of illustration that the yarn shown in Fig. 1 is 24s2 ply one inch in length and is twisted to five times the square root of the yarn count, it will contain seventeen turns. Then the yarn shown in Fig. 2 will have approximately forty two turns.

Although the moistening, stretching and twisting operations are preferably performed simultaneously as above referred to, Figs. 3 and 4 show the method of the invention as though it were being carried out in two separate steps. In Fig. 3 the yarn of Fig. 1 is shown afterbeing moistened and stretched so as to increase the count. The count will be found to be increased from about ten to about twenty percent. Since we are assuming that no twisting is being done until after the moistening and stretching operations are complete, the length of yarn shown in Fig. 3 will by reason of its longitudinal extension have fewer turns per inch than the yarn of Fig. 1.

In Fig. 4 the yarn which has been increased to a higher count, and hence been reduced in size, is shown after the maximum twist for this higher count has been imparted to it. Assuming a ten percent increase in count, the maximum twist obtained by the use of the constant 12 as a multiplier is about fifty turns per inch, or the equivalent of about fourteen times the square root of the original yarn count. Assuming a twenty percent increase in count the maximum twist obtained by the use of the constant 12 as a multiplier is about fifty five turns per inch, or the equivalent of fractionally less than sixteen times the square root of the original yarn count.

It will be understood that this corresponds with the maximum number of turns which the yarn is capable of receiving in the increased count to which it has been changed by the moistening and stretching. The drying of the yarn which now takes place causes the twist to set.

This setting of the 'twist causes the yarn to remain straight when the tension is released, and the yarn may be woven without difficulty into any sort of fabric desired. The yarn may be used for either warp or filling thread or both, and the weave of the fabric may be a plain one and one weave, a twill, a satin weave, or any of their derivatives in single, double, or multi-ply form.

In Figs. 6, 7 and 8 a small section of plain weave fabric is illustrated in which the warp threads 10 are of the highly twisted potentially elastic thread or yarn previously described, and the fillin threads 11 are of ordinary yarn having t e customary amount of twist and not hossessi'no elastic nrrmor.

ties. Inasmuch as the potentially elastic warps 10 are straight and show no inclination to kink or curl, the weaving operation is no more diflicult than with ordinary yarn. The straightness of the warps 10 may be seen in both Figs. 6 and 7.

Referring now to Fig. 5 of the accompanying drawings, the section of highly twisted thread of increased count of Fig. 4 is shown after the final moistening operation. This operation is performed after the release of the tension under which the highly twisted thread of Fig. 4 is dried. In Fig. 5 the yarn has returned to a lower count, that is, to a larger size. The greatly increased number of turns which have been imparted to the yarn are, however, retained in this reduced count.

A yarn has therefore been produced having a greater twist or number of turns per unit of length than the same yarn is ordinarily capable of receiving, that is, the yarn of Fig. 5 has a greater amount of twist than it was capable of receiving in its original count. This has been done by increasing the count through the application of moisture and tension so as to stretch the yarn to a higher count, and then apply to the yarn the maximum amount of twist which it is capable of receiving in the increased count without breaking. Then the drying of the yarn while maintaining it under tension sets the twist. The final moistening returns the yarn to a lower count, or increased size, with a substantial increase in the degree of twist which has been imparted to it while in the higher count. As a matter of fact the yarn returns to, and may go beyond its original count. In 5 it has been assumed that the yarn has returned exactly to its original count and contains from about fifty to about fifty five turns per inch depending upon the amount of stretch, within the range of from ten per cent to twenty percent, previously mentioned. This corresponds to a range of from about fourteen to fractionally less than sixteen times the square root of the yarn count.

While Fig. 5 has been drawn for the purpose of comparing the amount of twist in the yarn in its final state with the state of the yarn in its earlier stages, and with the maximum twist which the yarn is capable of receiving in its original count, the amount of twist of the yarn shown in Fig. 5 is actually so straight but assumes a corkscrew-like or helical spring shape when the final moistening in the free state takes place. n Fig. 8 of the accompanying drawings,

the section of fabric shown in Figs. 6 and 7, 1

great that the yarn does not remain 1 is illustrated after the final moistening and drying operations. It will be noted that the contraction of the warp threads 10 caused by the helical or spring-like shape which they nsenmn on amount. of the remarkablv high degree of twist which they contain has caused account of the much greater twist which has been imparted to the warp yarn. It will be understood that this increase in the retractile force of the fabric is of considerable importance when the elastic fabric is employed in the manufacture of waistbands, belts, garters and the like.

I claim:

1. The method of making elastic thread from relatively inelastic fibrous yarn which comprises increasing the original count of the yarn by moistening and stretching the yarn, imparting to the yarn while in such condition va greater amount of twist than the yarn was capable of receiving in its original count, drying the yarn in such stretched and highly twisted condition, relieving the tension upon the yarn, and subsequently moistening and drying the yarn in its free state, thereby reducing the count of the yarn but retaining therein the added amount of twist.-

2. The method of making an elastic thread from relatively inelastic fibrous yarn which comprises simultaneously twisting, stretching and moistening the yarn thereby increasing the original count of the yarn and imparting thereto a greater amount of twist than the yarn was capable of receiving in its original count, drying the yarn in such stretched and highly twisted condition, relieving the tension upon the yarn, and subsequently moistening and drying the yarn in its free state thereby reducing the count of the yarn but retaining therein the added amount of twist.

3. The method of making an elastic thread from a relatively inelastic fibrous yarn which comprises increasing the original count of the yarn by subjecting the yarn to the action of a steam bath and stretching the same while moistened thereby, imparting to the yarn while in such condition a greater amount of twist than the yarn was capable of receiving in its original count, drying the yarn while in such stretched and highly twisted condition, relieving the tension upon the yarn, and subsequently moistening and drying the yarn in its free state thereby reducing the count of the yarn but retaining therein the added amount of twist,

4. The method of making elastic thread from relatively inelastic fibrous yarn which comprises increasing the original count of the yarn by moistening and stretching the yarn, imparting to the yarn while in such condition a greater amount of twist than the yarn was capable of receiving in its original count, winding the yarn in such stretched and highly twisted condition upon a spool, drying the yarn while it remains-upon the spool, unwinding the yarn from the spool and relieving the tension upon the yarn, and subsequently moistening and drying the yarn in its free state thereby reducing the count of the yarn but retaining therein the added amount of twist.

5. The method of making an elastic fabric from a relatively inelastic fibrous yarn which comprises increasing the original count of the yarn by moistening and stretching the yarn, imparting to the yarn a greater amount of twist than the yarn was capable of receiving in its original count, drying the yarn in such stretched and highly twisted condition, relieving the tension upon the yarn, the yarn still being substantially inelastic and of increased count, weaving said yarn into a fabric, and subsequently moistening and drying the fabric while in its free state thereby reducing the count of the woven yarn but retaining therein the added amount of twist which causes the yarn to kink and become elastic.

6. The method of making an elastic fabric from a relatively inelastic fibrous yarn which comprises increasing the original countof the yarn by subjecting the yarn to the action of a steam bath and stretching the same while moistened thereby, imparting to the yarn while in such condition a greater amount of twist than the yarn was capable of receiving in its original count, drying the yarn while in such stretched and highly twisted condition, relieving the tension thereon, said yarn remainin in its increased count and still being su stantially inelastic, weaving the yarn into a fabric, and subsequently moistening and drying the fabric while in its free state thereby causing the woven yarn to return to a lower count but retaining the added amount of twist and thereby becoming elastic.

7. The steps in the method of making an elastic fabric which comprise increasing the original count of a yarn of relatively inelastic fibrous material by moistening and stretching the yarn, imparting to the yarn while in such condition a greater amount of twist than the yarn was capable of receiving in its original count and drying the yarn in such stretched and highly twisted condition.

8. The steps in the method of making an elastic fabric which'comprise increasing the original count of the yarn of relatively inelastic fibrous material by moistening and stretching the yarn, imparting to the yarn while in such condition a greater amount of twist than the yarn wascapable of receiving in its original count, winding the yarn upon a spool in such stretched and highly twisted condition, and drying the yarn while it remains in such condition upon said spool.

9. As a new article of manufacture, an elastic fabric containing relatively inelastic fibrous yarn having a twist equivalent to not less than about fourteen times the square root of the yarn count.

10. As a new article of manufacture, an elastic fabric containing relatively inelastic fibrous yarn having an amount of twist equivalent to substantially more than 12 times the square root of the yarn count.

In testimony whereof I aflix my signature.

OSCAR S. LAWTON. 

